A quick google search provided this:
To change the temperature unit from Celsius (°C) to Fahrenheit (°F) on a Victorinox Traveller Lite, follow these steps to access the settings menu:
Enter Setting Mode: Press and hold the Victorinox emblem (the button on the scale) for 8 seconds until the display flashes.
Change Unit: While the display is flashing, press the button briefly to toggle between units (e.g., Celsius/Meter, Celsius/Feet, Fahrenheit/Meter, Fahrenheit/Feet).
Confirm Selection: If no button is pressed for 3 seconds, the setting mode will automatically exit and save your selected unit.
